Abstract

Up to now, little has been understood about the way that airborne pollution is distributed spatially at head height and kerbside in the urban street grid. This paper reports on research in which a new monitor has been developed, validated and used to sample a small urban neighbourhood at finer temporal and spatial resolutions than has been achieved previously. The data show that pollution concentrations at head height vary radically within metres of each other. A method is developed for using the shape of the frequency distribution of pollutant concentrations to 'fingerprint' monitoring sites in terms of their pollution exposure at both average levels and at the extremes, and to compare the effects of climatic, seasonal and diurnal changes on pollution concentrations, as well as to help isolate effects of traffic management and other interventions on local ambient pollution concentrations. 'Space syntax' methods of analysis of street grid configuration, which have been shown to predict vehicular flows on the basis of representations of the geometry and topology of the street grid alone, were found to predict both average and extreme CO concentrations (r = 0.88, p = 0.0001) at street segment resolution in the urban grid.